Total anthocyanin content was measured by pH-differential spectrophotometry method following the procedure ofRapisarda, Fanella, and Maccarone (2000) with a slight modification. Five grams of frozen sample was extracted with 25 ml of pH 1.0 buffer containing 50 mM KCl and 150 mM HCl, as well as 25 ml of pH 4.5 buffer containing 50 mM sodium acetate and 240 mM HCl. Absorbance was measured at 510 nm and 700 nm with a spectrophotometer, using A=[(A510-A700) pH 1.0-(A510-A700) pH 4.5] with a molar extinction coefficient of cyaniding 3-glucoside of 29600. Results were expressed as milligrams of Cy-3-Glu equivalents per gram of fresh weight.